1. Field of the Invention
This document relates to a plasma display apparatus.
2. Description of the Background Art
FIG. 1 shows a structure of a related art plasma display panel. As shown in FIG. 1, the related art plasma display panel comprises a front panel 100 and a rear panel 110. The front panel 100 comprises a front glass substrate 101 and the rear panel 110 comprises a rear glass substrate 111. The front panel 100 and the rear panel 110 are coupled with each other in parallel at a given distance therebetween.
A scan electrode 102 and a sustain electrode 103 are formed on the front glass substrate 101 to maintain light-emissions of discharge cells through a mutual discharge therebetween. The scan electrode 102 and the sustain electrode 103 each comprise transparent electrodes 102a and 103a made of a transparent material, for example, indium-tin-oxide (ITO) and bus electrodes 102b and 103b made of a metal material. A scan signal for scan of the plasma display panel and a sustain signal for discharge maintenance of the plasma display panel are supplied to the scan electrode 102. A sustain signal is mainly supplied to the sustain electrode 103. An upper dielectric layer 104 is formed on upper parts of the scan electrode 102 and the sustain electrode 103 to limit a discharge current and to provide insulation between the scan electrode 102 and the sustain electrode 103. A protective layer 105 is formed of MgO for facilitating discharge conditions on an upper surface of the upper dielectric layer 104.
Address electrodes 113 are formed on the rear glass substrate 111 to intersect the scan electrode 102 and the sustain electrode 103. A lower dielectric layer 115 is formed on an upper part of the address electrode 113 to provide insulation between the address electrodes 113. Barrier ribs 112 are formed on the lower dielectric layer 115 to form discharge cells. A phosphor layer 114 is coated between the barrier ribs 112 to emit visible light for displaying an image.
The front glass substrate 101 and the rear glass substrate 111 are coalesced using a sealing material. After performing an exhaust process, an inert gas such as helium (He), neon (Ne), xenon (Xe) is injected into the inside of the plasma display panel.
A method for representing gray scale through a related art plasma display panel is shown in FIG. 2.
FIG. 2 illustrates a method for representing gray scale of an image of a related art plasma display panel. As shown in FIG. 2, a frame period (16.67 ms) is divided into eight subfields SF1 to SF8. The eight subfields SF1 to SF8 each comprise a reset period, an address period and a sustain period.
The duration of the reset period in one subfield is equal to the durations of the reset periods in the remaining subfields. Likewise the reset period, the duration of the address period in one subfield is equal to the durations of the address periods in the remaining subfields. An address discharge is generated by the voltage difference between an address electrode and a scan electrode during the address period. The duration of the sustain period increases at a ratio of 2n (n=0, 1, 2, 3, 4, 5, 6, 7) in each of the subfields. Since the duration of the sustain period of each of the subfields is different from one another, grey level of various images is represented by controlling the duration of the sustain period of each of the subfields.
A plasma display apparatus for representing gray scale of the images as described above is shown in FIG. 3.
FIG. 3 illustrates a related art plasma display apparatus. As shown in FIG. 3, the related art plasma display apparatus comprises a data driving board 310, a scan driving board 320, a sustain driving board 330 and a control board 340.
The data driving board 310 supplies an address pulse to an address electrode during an address period. The scan driving board 320 supplies to a scan electrode a reset pulse during a reset period, a scan pulse during the address period and a sustain pulse during a sustain period. The sustain driving board 330 supplies a sustain pulse to a sustain electrode during the sustain period. The control board 340 supplies data for controlling each of the pulses supplied from the driving boards 310, 320 and 330 to each of the corresponding driving boards 310, 320 and 330. The control board 340 will be described in detail with reference to FIG. 4.
FIG. 4 illustrates a control board of the related art plasma display apparatus of FIG. 3. As shown in FIG. 4, the related art control board 340 comprises an image signal receiving unit 410, an image signal processing unit 420 and a data arranging unit 430.
The image signal receiving unit 410 receives an image signal input from the outside, transforms the image signal into 8-bit initial image data, and outputs the 8-bit initial image data to the image signal processing unit 420.
The image signal processing unit 420 transforms the initial image data received from the image signal receiving unit 410 into image date suitable for the plasma display panel through an inverse gamma correction process, a gain control process, a half-toning process and a subfield mapping process.
The data arranging unit 430 arranges the image date received from the image signal processing unit 420 by each of subfields, and then transforms the arranged image date into addressing data. The data arranging unit 430 outputs the addressing data to the data driving board 310 through a cable 350 of FIG. 3.
Since a plasma display panel supports high definition, the number of channels of the cables 350 for transmitting the addressing data from the data arranging unit 430 of the control board 340 to the data driving board 310 increases. Accordingly, there is a problem in that the manufacturing cost of the plasma display apparatus increases.
Further, since the larger the size of the plasma display panel is the longer the length of the cable 350 is, a signal loss of the addressing data transmitted through the cable 350 and cross-talk are generated. In particular, when the addressing data is transmitted using a transistor-to-transistor (TTL) method, the signal loss and the generation of a noise increase.